Thing with a missile, is where would it be launched from?
And if a missile takes the place of a plane, then it raises questions about Flight 77. Only other way is to say the flight never existed. But that would make a massive weak spot for anyone to plan something that way, for a long list of reasons, so it doesn't make sense.
Another claim is that explosives had been rigged to release upon the ring walling material being broken. From what I've seen, that's stayed consistent with the evidence.